Answer C is not a good answer here,
GGIBA003@FIU.EDU, because it does not describe a problem inherent in the structure of the argument itself. It's the kind of thing that the author could respond to be saying "so what? I can provide that if you want." A good flaw answer has to be something that the author, upon hearing it, would be forced to say "oops, my bad, you're right, I made that mistake." Answer C doesn't necessitate that sort of response.
I think it's fair to think of this as a numbers and percentages flaw, because a change in ranking is sort of a percentages idea while a decrease in pollution is definitely a numeric one. But I think of this one as being what we call a "Relativity Flaw," which is where the author treats a relative relationship, like "better" or "more expensive," as if it proves an absolute claim like "good" or "expensive." To illustrate, the jeans I am wearing right now were more expensive than the t-shirt I am wearing, but the jeans were not at all expensive (I think I paid about $12 for the jeans and maybe $6 for the t-shirt; thank you, Marshalls!)
In this case, the river getting better
relative to other rivers (dropping from worst to third-worst) does not prove that it actually got better (an
absolute claim rather than one that shows a comparison). That's the flaw, and that's what we need the correct answer to describe, forcing the author to respond by saying "oops, my bad!"
Adam M. Tyson
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